2005 Chevy Tahoe rear air issue.

Discussion in 'Chevy Tahoe Forum (GMC Yukon, Cadillac Escalade)' started by sutphen1, Nov 18, 2012.

  1. sutphen1

    sutphen1 New Member

    Hello...New to the forum. I was working on my 2005 Tahoe . The issue is a code that comes up from the rear air (B0434). The problem is the rear air will not switch from hot to cold. Both lines feeding the rear have hot and cold pumping through them. The door that the hot and cold actuator is connected to moves with no obstruction by hand. The steps I have taken thus far are fixing the suggested part that the Bulletin listed as the cause of the code. The air temp actuator and the auxiliary mode actuator both replaced. All parts are the most current to flash upgrades. I cant get the air to blend from cold to warm. All systems reflashed and then the code fires back. When the diagnostic is hooked in the parameters for all actuators are within range and the system can be used with no trouble. As soon as We release the truck after the flash the code comes back and the sytem goes to full cold in the rear air only. Front air has no issues at all. Really lost at this point...first time I have not had a bulletin repair suggestion fix the issue...i have not had really any issues with my Tahoe but this came out of the blue..We just got out of the summer months and needed warm air in the back..this is when i noticed the problem. i have not performed any recent work as far as electrical or battery. Any help would be great. Thank you!! Matt. Part for aux module was 15832319.
  2. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    The Tech II must be providing something that is missing under the current conditions.

    It appears, that your current "normal" position for the temp/blend door is full cold, that may be because either battery, or ground, is missing. When the Tech II is plugged in, the missing condition (battery, or ground) is feeding through the tech II.

    Edit: have you checked all of the fuses?
  3. sutphen1

    sutphen1 New Member

    I will check fuses tomorrow. Can these have a ground that goes bad? I have had to search force volt source problems and ground issues before in cars i have owned in the past and dread it. I see what you mean by the Tech II Working and thetruck cant function off the Tech...I have just began into this so will do some further searching. I wonder if the modual in the rear control behind the center councel could be bad. I am begining to think I may have replaced the wrong modul??? The bulliten did print and read Modul assembley- auxiliary heater & ac control. I took that as the one in the rear housing by the third row seat. Either way I will continue the hunt for more information and possible causes. Thanks a bunch for responding.
  4. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Yes, the grounds can be a problem. I can't speak of yours, but the '05 Envoy, I had, was notorious for bad grounds, mostly loose and corroded.

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